Sanitary napkin



June 17, 1952 c. RlcKARD ET AL SANITARY NAPKIN 2 SHEETS-SHEET 1 FiledAug. 4, 1950 Nrn AMA,

d. m W. J m e n fm June 17, v1952 c. l. RICKARD ET AL SANITARY NAPKINzlsl-lEETs-SHEET 2 Filed Aug. 4, 1950 Patented June 17, 1952 SANITARYNAPKIN Charlotte I. Rickard and Kenneth J. Harwood,

Neenah, Wis., assignors to International Cellucotton Products Company,Chicago, Ill., a corporation of Delaware Application August 4, 1950,Serial No. 177,702

(Cl. 12S-290) Claims. 1

This invention relates to improvements in sanitary catamenial napkinsand the principal .object of the invention may be said to be that ofproviding a sanitary napkin of greater eiliciency than those heretoforeavailable.

Efficiency of a sanitary napkin as herein referred to, takes intoaccount many factors and characteristics of the napkin, for example, (a)the absorption capacity of the napkin, (b) the absorption spreadingcharacteristics thereof, (c) the tendency of the napkin to move from itsproper place due to body movement and muscular action, (d) the weightand bulk of the napkin and its reaction to the pressures to which itissubjected when worn, and (e) comfort characteristics of the sanitarynapkin when worn. Other characteristics and qualities may also have abearingr on this matter of efficiency but those just referred to areprobably the most important and the present invention is concerned withimprovements which relate mainly to the aforesaid characteristics. e

In connection with the details of construction of a sanitary napkin toattain high efliciency, it is of course important to consider thepracticability of the structure from a manufacturing viewpoint.Commercial considerations require that a construction be such that itmay be massproduced at high speed by automatic machinery at very lowcost.

The present invention aims to provide a sanitary napkin which embodies amore eilicient construction and which improved construction may bemass-produced at high speed by automatic machinery and at low cost asaforesaid.

Other objects and advantages of the invention will be understood byreference to the following specification and accompanying drawingswherein the invention is illustrated in several embodiments.

In the drawings, Figure 1 is a fragmentary perspective which embodies alongitudinal section through one form of a sanitary napkin embodying theinvention;

Figure 2 is a view similar to Figure 1 but showing another form ofconstruction;

Figure 3 is a perspective illustration of one component of the padstructure shown in Figure 2;

Figure 4 is a section on the line ll--4 of Figure 2;

`Figures 5, 6, 7 and 8 are side elevations of other forms ofconstruction of a component of a sanitary napkin according to thepresent invention; Figure 9 is a perspective illustrating approxi-(original No. 1,857,854, May 10, 1932).

mately the condition to which the absorbent pad portion of the napkin isfolded when worn; and

Figures 10 and 1l are sections, respectively, on the lines lll-I0 andII-II of Figure 9.

The sanitary napkin construction shown in Figure 1 comprises anabsorbent pad body` or unit I enclosed in a wrapper of gauze 2 or othersuitable material. Arrangement of the wrapper about the absorbent padmay be in accordance with conventional practice and is not illustratedin detail. In accordance with such conventional practice the wrapper hasend extensions 3 and at the front and rear ends respectively of theabsorbent pad body, these extensions being usually employed forattaching the napkin to a supportingl belt or to otherwise support thenapkin when worn. k

The pad body l comprises top and bottom or outer face layers 5 and 6 ofabsorbent crepe tissue paper, these layers being of substantially likelength and having their end portions pressurebonded together asindicated at 1 substantially in accordance with the teaching of UnitedStates Patent No. Re. 21,706 Glomstead, May 9, 1939 Inside layers 8 and9, also of suitable absorbent material, are provided intermediate thelayers 5 and 6.

vThe material employed in the layers 5, B, 8 and 9 may -be crepe tissuepaper, preferably arranged `with the creping extending lengthwise of thelayers. The layers 5 and '6 may advantageously consist of about tenplies of crepe tissue paper, the layer 8 of about ten plies and thelayer 9 of about eight plies, the layer 9 being treated as taught inUnited States Patent No. 1,863,333 to Heitmeyer June 14, 1932, to formthis layer into a so-called equalizer, i. e., a device having a capacityof accelerating the spread of fluid absorption lengthwise within thepad. Other suitable absorbent materials may be employed in theconstruction of any or all of these layers as will presently appear.

The layer 8 is of less length than the outer layers 5 and 6, being hereshown as of about three-fourths the length of said outer layers. Saidlayer 8 has one end bonded to the front ends of the layers 5 and 6 bybeing extended between the end portions of the layer where they arecompressed as indicated at 1. The other end of said layer 8 terminatesas indicated at I0 at a considerable distance from the rear end Hof the,pad. The layer 9 which, as above indicated, is. preferably compressedalong longitudinal zones'tofform aso-called equalizer is shorter thanthe layer 8.1and

CII.

portion is adapted to remain in a flat bodyhug-V Y ging condition whenthe napkin is worn. Similarly the rear end portionof the napkin isreduced in thickness to the combined thickness of only the outer layersand G as indicated at l2. The reduced rear end thickness indicated at I2is more or less gradually increased tothe full thick-v ness of the main:pad body through the agency of the short rear end portion Baof theintermediate layer 8.

The described arrangement of pad layers results in a pad having itsmaximum thickness and absorption capacity in that quarter (indicated atI3` in Figure l) of the length of the napkin immediately in front of themiddle of the pad part of the napkin between its front and rear ends.v

Another construction is shown in Figure 2 wherein the napkin embodies apad Ill enclosed in a suitable gauze wrapper I5 having front and rearattachment tab extensions i6 and Il, `respectively.

The absorbent pad body i4 com-prises upper and lower or outer facelayers IB and I3 lrespectively, each of which may consist of around tenplies of crepe tissue paper. Said outer plies are oflike length and havetheir ends pressure-bond-` ed together as indicated at 23.

Between the multi-ply tissue layers i8 and I9 therev is an absorbentfiller structure which, in this instance, comprises upper and lowerlayers 2| and 22, respectively, and an intermediatelayer 23.

l'.iherupper layer 2l may consist of a layer 24 (see also Figure 3) offinely divided cellulose ber or so-called Huff on a supporting orbacking sheet of crepeV tissue paper. The said fluff layer'2'4 has athickness A for about one-half of its width and then tapers from about amid-point of its with at B to a very thin or featheredge at C. The layer22 may be similar to the layer 42i or it may be of substantially uniformthickness `from end to end as shown in Figure 2, being, however,constructed of a layer` of said uii material on a supporting or vcarriersheet of crepevtissue or similar material. 'I'he'intermediate layer 23may be formed of a layer of said fluff material between upper and lowerconnning sheets 26 and 2l, respectively',"i` crepe tissue paper or othersimilar material and this intermediate layer 23 may be made intoV aso-called equalizer element by pressure treatment according'to theteaching of the above mentioned Heitmeyer patent. As shown in Figure 4the intermediate layer 23 is provided with longitudinally extendingalternately arranged relatively compressed zones 23 and incompressedzones 29 as 'a result of said pressure treatment.`

A baiile sheet 33 may be positioned in the absorbent ller unitintermediate the equalizer 23 and the upper Vor lower layer 2l and 22,preferably the lower layerlas shown. Such baille sheet may consist ofone or two (or more) plies of crepe tissue paper suitably treated toimpart the de# sired degree of moisture-proofness thereto. It ispreferable that such moisture-proofness be adequ'ate enable thebaille-"sheet towithstand' uid penetration until a substantial volume ofuid has been received in the pad above the baiiie sheet and until thefluid pressure is built up to a point where it can force the fluidthrough the baille sheet. The iiui material employed in the layers 2|,22 and 23 and the tissue carrying or supporting plies associated withsaid layers are preferably of a highly absorbentcharacter so that theywill readily absorb fluid delivered thereto.

In the construction in Figures 2 to 4 inclusive, the layer 2| with itstapering thickness portion imparts to the pad M tapering thicknesscharacteristics similar torthose of the pad I shown in Figur-el. In-the.Figure 2 arrangement the quartei-portion 3L ofthe over-all pad lengthimmediately in front ofV the center of the pad embodies the maximumthickness of the pad body portion and provides the maximum absorptioncapacity portion of said pad.

Tapered thickness absorbent pads may be made by employing an absorbentsection suohas represented in Figure 5 which is made from-a web. of thecharacter represented in Figure 6. In Figure 6 a layer 32 of ui isdeposited on a crepe tissue or similar carrying sheet 33. The layer 32has a centrally located portion. of uniform. .thickness D and endportions which taperV from the. thickness D to featheror near featheredges as. shown. Such a web. is folded on itself at about its mid-pointindicated at-34, the carrying sheet 33 being on theo-utside, thereby toform the folded structure .shown in Figurer. The folded,.tapered padelement shown in kFigure 5 has `a -main portion having two thicknesses Din relatively superposed relation to, each other and two tapered endportions in relatively superposed relation to thereby provide a padhavingl about one-half its length of uniform thicknesscorresponding totwo times D and the otherhalf of its thickness tapering from said mainthickness to a thin edge 35.

An absorbent insert such as shownin Figures 5 and 6 may be substitutedfor the-multiplelayer insert between the outer layers IBVandVIS intheFigure 2 constructi011.orif desired, the entire absorbent pad 4may berepresentedl by the structure shown in Figure 5 which, in that casewould be made of appropriate lengthv to correspond to the full desiredpad length, `and Acovered with a suitable wrappernsuch as the wrappers 2and l5 of Figures l and 2 respectively.

The form ofpad component shown in Figure? comprises a wrapper 36 ofcrepe tissue paper or other suitable material which is initially spreadout in flat web form and on which is deposited a layer 3l of nuff, thelayer being deposited so as to'have a uniform thickness over aboutone-,half the width of the layer "andgatapering thickness as shown overthe remaining portion of the width of the layer. A web Aof equalizermaterial 38 (or a `baile element) `is next deposited on top of theufflayer`r 31 if suchf equalizer or baiiiejare desired, and anotherfluff layer 39 Y,similar to the fluit layer 3l is deposited on theequalizer. The marginal portionsv 36ay and SSb'ofthe wrapper sheet 36are then folded over the iluilv layer V39 and into mutually lapping-relationship as shown to confine said uffmaterial.

Another tapered form of pad construction can be attained as Vshown inFigure S where a series of layers 40, 4l, 42 and 43 of progressivelyincreasing length are assembled together to lform a more or lessstep-tapered pad. Thelayers-may be vmade of superposed plies of crepetissue paper or of yiiuifmaterial with or without backing sheets, andeither equalizer or baffle strips or both, may be incorporated at anydesired location in such a step-tapered structure.

The pad body structures represented in Figures '7 and 8 may be used inthe lsame manner set forth above in respect "of the structure shown inFigure 5. Y

Pad body material having the cross-sectional shape shown in Figures 5, 7and 8 may be made in long lengths and rolled up into supply rolls forsubsequent delivery to pad forming machines which are equipped withinstrumentalities to cut of'l successive end portions of the requiredwidth to form the desired pad units. A typical machine of this characteris represented in United States Patent No. 2,262,275 Fourness andGreiner, November 11, 1941. y

The various elements or layers ofthe pad body are of substantiallyvconstant thickness from side to side of the pad in each elementary unitof length thereof as shown in Fig. 3, said thickness varying however,from end to end, in some of the layers as already explained. Padelements of such uniform side to side thickness are obtained when vtheseelements are cut one byone from the end of a long supply strip of thematerial as above explained, the said supplfy strip being formed withtransverse cross section corresponding to the desired longitudinalsectional form of the element.

Absorbent sanitary napkin pads have been made in various laminatedarrangements in which certain layers terminate short of the ends of thepad body so as to provide end portions of reduced thickness. Pads somade have been symmetrical in form and the absorbent capacity thereofhas been substantially uniform throughout a major portion of the lengthof the pads, such portion being centered between the ends of the pads.

Conventional sanitary napkins of this general character have beenevolved over a period of about the last thirty-five years, beginning.with an all-crepe tissue paper pad of rectangular pad and uniformthickness from end to end. During these years of development, one of thepersistent complaints has been that the absorbent pads have a tendencyto wet or strike through from the body side to the outside. Absorbedfluid usually penetrates the entire pad thickness in a zone intermediatethe pad ends and usually,

nearer to one end of the pad than to the other. This absorption tends tospread lengthwise of the pad from the zone of application. Of course thespread of absorption depends to a considerable extent upon the amount offluid delivered to the napkin and the length of time that the napkin isworn. Due to the discomfort experienced when a napkin becomes very wetthe tendency is to dispose of the napkin long before a major portionof'its absorptive capacity has been used up. This obviously reflectsconsiderable inefficiency in the conventional pad structures.

When a sanitary napkin is applied it is normallyfolded lengthwiseapproximately as represented in Figure 9 where the front end of the padis represented at 44 and the rear end at 45; intermediate the front andrear ends, the pad is folded longitudinally upon itself approximately asillustrated and this longitudinally folded portion is subjected toconsiderable compressive force between the legs of the wearer, wherebythe normal thickness of the folded structure is reduced from somethingabout as represented by the dotted line showing at 46 (Figure 10) to thefun une showing at 4s. `with the conventi'entiV uniform thickness padsthis compression tends to increase the capillary ow of fluid toward therear end of the pad and when the wearer has occasion to sit down, thereis necessarily a tendency to further compress the pad material andv toexpress some of the absorbed fluid to the out-A side of the pad. Theresulting adverse effects on the comfort characteristics of the napkinare self-evident.

This uniform cross-section of conventional pads also readily permits thedisplacement of the pad in a longitudinal direction unless theattachment tabs have been pulled up soy tightas to thereby create theirown discomfort.

The described improved. construction withv a tapered thickness rearportion provides maximum absorption capacity in the area of the padVThis reduction in bulk in the rearward portion ofv the pad serves toprevent the application of a significant portion of the capillaryproducing compression on said rearward portion and also to prevent theapplication of fluid expressing pressure thereon as often occurs withconventional uniform thickness pads as above explained. The forwardthicker portion, being subjected to the usual capillary increasingcompression will, however, effectively take up and hold the fluidreaching the same. By employing an equalizer strip such as the strip23-in Figures 2 and 4 in the pad body rearward absorption may bepromoted interiorly of the pad and permits extended Wear of the pad ifdesired until even its rear portions are quite moist. If preferred, theequalizer strip may be terminated somewhat short of the rear end of theintermediate plies to accordingly control the rearward spread of fluidabsorption.

The absorption capacity of the described tapered thickness pad structureis substantially equal in a practical sense to the absorption capacityof a conventional uniform thickness pad having a bulk of absorptionmaterial which i's greater than that of thetapered thickness pad by anamount approximately equal to that which has been'eliminated from therear portions of the described tapered structures to form the taper.Hence, efficiency of the described tapered:

structure is in fact substantially higher.' than the absorbingefficiency of the conventional unform thickness pad.

Because of the reduced thickness of the rear portion of the pad, the padis somewhat more flexible lengthwise and therefore may be more easilycentered on the body and caused to conform to the anatomy, therebyimproving the comfort characteristic of the napkin.

The longitudinally tapering or wedge shape of. the napkin when foldedfor application'to lthe body, provides a front portion whichu istransversely enlarged, as from side 48 to side 459V in Figure 10, ascompared with the dimension in a" corresponding direction of arearwardportion as represented in Fig. 1l. This transverse frontenlargement tends to anchor the pad against rearward displacementincident to body and' muscular` activity so that the improved pad has aypronounced tendency to remain in place'. this being animportantimprovement overtheprior

